PTP over DWDM Transport

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Dense Wavelength Division Multiplexing (DWDM) is a transmission technology that enables greater fiber capacity, longer transmission distances, and higher data rates by multiplexing multiple wavelengths into a single fiber

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DWDM is used in telecom networks, data centers, as well as in enterprise networks, providing a scalable solution to meet growing data rate demands.

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This test case was developed to verify reliable PTP operation over coherent ZR/ZR+ DWDM optics installed in the Telecom Boundary Clocks, ensuring that transport solutions meet scalability and performance requirements.

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At this year's testing event, we had more vendors, five in total, supporting PTP over DWDM-enabled tunable ZR/ZR+ optics compared to last year’s testing event.

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[[~[~[Figure 91: PTP over DWDM transport - General Test bed setup~>~>image:487250136888508417_dwdm.png~|~|alt="Figure 91"~]~]>>attach:487250136888508417_dwdm.png||target="_blank"]]

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For all the tests, the setup consisted of a Telecom Grandmaster (T-GM), two cascaded Telecom Boundary Clocks (T-BCs), and a frequency/phase analyzer.

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For some test cases, an emulated T-GM was used: either the Calnex Paragon neo, Calnex Paragon neo-A, or the Keysight Time Sync Analyzer. In those tests, the same device that served as the emulated T-GM also served as the frequency/phase analyzer. For other tests, a real T-GM, the Microchip TimeProvider® 4500, was used in combination with either the Calnex Paragon neo or Calnex Paragon neo-A. These tests were run with either a 100 or 400 Gigabit Ethernet (GbE) tunable ZR/ZR+ DWDM optic between the two T-BCs, with the links between the T-GM and T-BC-1 and T-BC-2, and the frequency/phase being standard grey optics.

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All combinations tested met the limits for Class C media converter pairs, as per ITU-T G.8273.2, Appendix V, table V.1, with some combinations even meeting the max|TE,,L,,| limit of 10 ns for two Class D T-BCs.

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These results show that modern T-BCs and coherent pluggable optics do not cause compliance issues with high-accuracy time synchronization. The findings suggest that T-BCs, synchronized via coherent ZR/ZR+ DWDM optics, can meet the stringent phase and time synchronization requirements common in modern networks, proving that high-capacity optical transport and precise time synchronization can coexist without sacrificing performance.

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|=(Emulated) Telecom Grandmaster|=Telecom Boundary Clock - 1|=Telecom Boundary Clock - 2|=Frequency/Phase Analyzer

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|Keysight Time Sync Analyzer|Raisecom RAX721-T-4C24|HPE PTX10002-36QDD|Keysight Time Sync Analyzer

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|Keysight Time Sync Analyzer|Raisecom iTN8800-A|HPE PTX10002-36QDD|Keysight Time Sync Analyzer

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